A disk drive includes a stop, a head stack assembly and a latch having a
latch arm that is movable between a closed position and an open position.
The latch includes a first retainer that urges the latch arm toward the
open position, and a second retainer that urges the latch arm toward the
closed position. The latch includes a mover that contacts the latch arm
upon a sufficient shock to the disk drive and causes the latch arm to move
to the closed position. The disk drive includes an actuator motor that
momentarily urges the head stack assembly against the latch during startup
of the disk drive, thereby moving the latch arm to the open position.